There are currently available several types of door closing mechanisms which both urge the door to a closed position and slow the closed speed of the door to prevent the door from slamming into the door frame under the force of the closing mechanism. Generally, however, these devices are quite limited in their durability and function. Some lighterweight devices include means for holding the door in the open or partially open position but provide little else in the way of door opening and closing control and are operative to allow the door to be opened in only one direction. U.S. Pat. No. 3,246,362 teaches a mechanism which can be used on double swinging doors; is capable of holding heavier doors in the open position and includes means for independently regulating the rate at which the door closes and latches. While this device was an improvement over door closers previously available, it would also be a desirable feature to be able to readily adjust the force which must be overcome to open the door while independently being able to regulate the closing and latching speed. Additionally, it would be beneficial to be able to selectively disengage any mechanism which holds the door in the open position while being able to regulate the rate at which the door opens and thereby effectively provide an adjustable shock absorber within the closing mechanism.
Another shortcoming with double swinging door closing mechanisms presently available, including that identified above, is their need for the operative elements to be immersed in oil or other hydraulic fluid, thereby necessitating the use of an oil seal about the rotating shaft or spindle. Such a seal is highly subject to leakage which constitutes a safety hazard and can, of course, have a very damaging effect on any carpet below. It would be highly desirable to provide a heavy duty door closing mechanism which mounts the spindle in a dry sump and thereby eliminate the need for such a seal. As will be described, the door closer described herein includes each of the foregoing beneficial features.